If only the floating point stack is empty, .S displays
the integer stack items in one column, one item per line,
both in hex and in decimal like this (the first item is topmost):

12345 HEX 67890 .S
424080 [00067890]
12345 [00003039] ok

If both stacks ar not empty, .S displays both stacks, in two
columns, one item per line

HEX 123456.78E90 ok
DECIMAL 123456.78E90 .S
291 [00000123] 1.234568E+95
1164414608 [45678E90] ok

Confusing example? Remember that floating point input only works
when the BASE number is DECIMAL. The first number looks like
a floating point but it is a goodhex double integer too - the number
base is HEX. Thus it is accepted as a hex number. Second try
with a decimal base will input the floating point number.

If only the integer stack is empty, .S shows two columns, but
he first columns is called lt;stack emptygt;, and the
second column is the floating point stack, topmost item first.